1. Field of the Invention
The present invention relates to an ejector cycle including an ejector. The ejector cycle is suitably used for a vapor compression refrigerator for cooling a compartment.
2. Description of Related Art
In an ejector cycle described in JP-A-6-11197, refrigerant is decompressed and expanded in a nozzle of an ejector so that gas refrigerant evaporated in an evaporator is sucked, and pressure of refrigerant to be sucked into a compressor is increased by converting expansion energy to pressure energy. In the ejector cycle, refrigerant discharged from the compressor is circulated to a condenser (radiator) so as to radiate heat absorbed in the evaporator. The refrigerant cooled in the condenser is decompressed and expanded in iso-enthalpy, and refrigerant evaporated in the evaporator is drawn into the ejector by pumping operation due to entrainment of high-speed refrigerant jetted from the nozzle. That is, by the pumping operation generated in the ejector, low-pressure side refrigerant circulates a gas-liquid separator→the evaporator→the ejector→the gas-liquid separator, in this order. Accordingly, when a pumping capacity generated in the ejector reduces, coefficient of performance (COP) of the ejector cycle is decreased. Accordingly, it is difficult to sufficiently improve the COP in the ejector cycle. Here, the COP is a ratio of a cooling capacity generated in the evaporator to a consumption power of the compressor.